JP4469791B2 - Optical element protection method and device manufacturing method - Google Patents

Description

  The present invention relates to an optical element protection method, a lithographic apparatus, and a device manufacturing method.

  A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, also referred to as a mask or reticle, may be used to create a circuit pattern to be created on an individual layer of the IC. This pattern can be transferred onto a target portion (eg including part of, one, or several dies) on a substrate (eg a silicon wafer). The transfer of this pattern is typically by imaging onto a layer of radiation sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. In known lithographic apparatus, a stepper irradiates each target portion by exposing the entire pattern onto the target portion at once, and the pattern is scanned by the radiation beam in a given direction ("scanning" direction). There are scanners that irradiate each target portion by scanning while scanning the substrate in parallel or antiparallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by printing the pattern on the substrate.

  The size of features that can be imaged on a substrate in a lithographic apparatus is limited by the wavelength of the projection radiation. It is desirable to be able to image small features when making high density device integrated circuits and thus requiring high operating speeds. Most modern lithographic projection apparatus use ultraviolet light generated by mercury lamps or excimer lasers, but it has been proposed to use radiation with wavelengths as short as 13 nm, for example. Such radiation is referred to as extreme ultraviolet (EUV) or soft x-ray, and possible sources include, for example, laser-excited plasma sources, discharge plasma sources, or synchrotron radiation from electron storage rings.

  The EUV radiation source is typically a plasma source, such as a laser excited plasma or a discharge source. A common feature of all plasma sources is fast ions and atoms that are emitted from the plasma in all directions. These particles can be detrimental to collector and condenser mirrors, which are brittle in surface and are generally multilayer mirrors. This surface progressively deteriorates due to the impact of particles emitted from the plasma, or sputtering, and thus reduces the lifetime of these mirrors. This sputtering effect is particularly problematic for collector mirrors. The purpose of this mirror is to collect the radiation emitted by the plasma source in all directions and direct it towards other mirrors in the illumination system. This collector mirror is very close to and in line with the plasma source and thus receives a large flux of fast particles from this plasma. Other mirrors in this system may generally be shielded to some extent, so they are generally not significantly damaged by sputtering of particles emitted from this plasma.

In order to prevent damage to the collector mirror due to debris particles, for example, as described in Patent Document 1 and Patent Document 2, a gas barrier has been proposed. The disadvantage of such a gas barrier is that not only the high speed particles pass through the channel of the barrier structure, but also some of the particles collide with the gas barrier, thereby producing secondary particles, which are in the optical element. It may be deposited. This deposition may damage the optical elements and degrade their optical properties. Moreover, such deposits are usually difficult to remove. Therefore, alternative methods are needed to address this problem for this reason.
US Pat. No. 6,756,912 US Pat. No. 6,359,960

  One aspect of the present invention is to provide a method for protecting an optical element. A further aspect of the present invention is to provide a device manufacturing method. Yet a further aspect of the invention is to provide a lithographic apparatus.

  According to a first embodiment of the present invention, there is provided a method for protecting an optical element of a lithographic apparatus including an optical element and a radiation source, wherein one or more elements selected from B, C, Si, Ge and / or Sn are included. Providing a material comprising, and causing the radiation source to remove at least a portion of the material during use, thereby providing a depositable material, and at least a portion of the depositable material to the optical element Disposing the material to deposit thereon.

  According to another embodiment of the invention, there is provided a radiation source and a lithographic apparatus comprising one or more parts selected from a gas barrier, a support, an apparatus wall, a chamber wall of the radiation source, and an edge of the opening. A method of protecting an optical element; wherein the radiation source provides a plasma containing Sn in use, the method providing a) a plasma containing Sn, thereby depositing Sn on the one or more components Providing an object; b) providing an optical element in the apparatus; and c) providing a plasma containing Sn thereby providing an Sn deposit on the optical element.

  According to yet another embodiment of the invention, a device manufacturing method provides a lithographic apparatus including an optical element and a radiation source; forming a radiation beam from radiation generated by the radiation source; patterning the radiation beam Projecting the patterned beam of radiation onto a target portion of the substrate; providing a material comprising one or more elements selected from B, C, Si, Ge and / or Sn; and The source is allowed to remove at least a portion of the material during use, thereby providing a depositable material, and so that at least a portion of the depositable material is deposited on the optical element. Placing the material.

  According to yet another embodiment of the invention, an illumination system in which the lithographic apparatus is configured to condition a radiation beam; patterning configured to provide a pattern in a section of the radiation beam to produce a patterned radiation beam. A support configured to support the apparatus; a substrate table configured to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; an optical element; a radiation source One or more parts of the lithographic apparatus, including the gas barrier, the support, the apparatus wall, the walls of the radiation source chamber, the electrodes, and the edges of the opening, B, C, Si, Ge and / or Sn And a component having a deposit containing one or more elements selected from the above, wherein the deposit has a layer thickness of 5 to 200 μm.

  Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference symbols indicate corresponding parts, and in which:

  In an embodiment of the invention, this material is supplied to at least a part of a gas barrier arranged in the lithographic apparatus. In another embodiment, a method is provided for supplying this material to a support, an apparatus wall, a wall of a radiation source chamber, and / or an edge of an apparatus disposed in a lithographic apparatus. In yet a further embodiment, a method is provided for supplying this material to at least a portion of one or more electrodes of a radiation source.

  In one embodiment, the radiation source is a plasma source including a Xe radiation source, a Li radiation source, or a Sn radiation source. Such sources, as well as other known sources, produce particles, such as ions, electrons, clusters, particles, liquid particles, electrode erosion, etc., in addition to radiation. In yet a further embodiment, the source is a laser excited plasma or a discharge source. In a further embodiment, at least a part of this material is transferred by particles from the radiation source from parts of the lithographic apparatus, for example from the support, heat shield, device wall, radiation source chamber wall, device edge, gas barrier, etc. Removing, in which case these particles have an energy in the range between about 0.1 keV and 10 keV, for example 1 keV or more.

  Particles from this source strike the surface of the parts of the lithographic apparatus, thereby creating other particles (ie secondary particles). However, hitting the material of the present invention results in a depositable material (also secondary particles) that may be deposited on the optical element, which causes the lithographic apparatus to be exposed to particles hitting parts of the lithographic apparatus. Depending on the type of material used, secondary particles such as Fe, Al, Cu, Mo, W, Ni, and / or Ti are emitted, which deposit on the optical element and can be easily removed from this optical element Not different from the prior art methods. Thus, in yet a further embodiment, at least a portion of the material applied to one or more parts of the device may cause collisions of particles from a radiation source with the material, irradiation of the material (eg, laser ablation). Or similar) and / or transfer of thermal energy to this material. In this way, removal of at least a portion of this material occurs during use of the device. For example, when Sn material is applied to an electrode, due to heat, Sn material may scatter from this electrode, thereby creating a depositable material. This may deposit on the optical element and / or other parts of the lithographic apparatus. When deposited on other parts of the lithographic apparatus or when the material is applied to such other parts of the lithographic apparatus, for example a gas barrier, for example, particles from the source and / or secondary particles May remove at least a portion of this deposit or material, thereby allowing deposition on the optical element. Also, one method or one of the other methods described above, such as irradiation, thermal energy transfer, etc., may produce a depositable material from the material of the part of the lithographic apparatus. Thus, a number of deposition and redeposition mechanisms are possible, as shown in the following table:

The parts ^{* of} the lithographic apparatus here are for example gas barriers, supports, heat shields, apparatus walls, radiation source chamber walls and apparatus edges, but not electrodes. The material on the electrode, if any, is shown in the leftmost column.

  The method or mechanism (a1) is a method in which the radiation source is an Sn radiation source, and Sn is provided as a deposit on an optical element, for example, a collector mirror. This is a primary process (indicated by step (1)). For example, Sn material from a source is first deposited on a portion of (1) a lithographic apparatus, and this deposit is then at least partially removed by Sn and / or other particles from the source (step ( 2)), higher order processes are also included when it results in Sn deposits on the optical element. This latter process is shown in this table as method or mechanism (a2). This is a secondary process because it may include higher orders, but the material may be deposited and removed several times before finally depositing on the optical element.

  In one variant thereof, this material can be provided in a part of the lithographic apparatus. For example, particles from the Sn source or other particles (step (1)) remove at least a portion of this material (step (2)), thereby resulting in deposits on the optical element. This is a secondary process shown as (a2b). Deposits made on the optical element may include materials derived from materials on parts of the device (materials containing one or more elements selected from B, C, Si, Ge and / or Sn). May also include Sn from the source (according to the mechanism of (a1) and / or (a2)).

  The same three methods / mechanisms apply to non-Sn sources, for example Xe or Li discharge sources, which may have Sn on the electrodes (methods (b1), (b2) and (b2b)). The method / mechanism (b1) is a method / mechanism in which the radiation source is a non-Sn radiation source, Sn is present on the electrode, and Sn is deposited on an optical element, for example, a collector mirror. This is a primary process (indicated by step (1)). For example, Sn material from the electrode (step (1)) is deposited on a portion of the lithographic apparatus, and this deposit is then at least partially removed by particles and / or Sn from the source (step (2). )), Higher order processes are also included when it results in Sn deposits on the optical element. This latter process is shown as method (b2) in this table. This is a secondary process because it may include higher orders, but the material may be deposited and removed several times before finally depositing on the optical element.

  In one variant, the material according to the invention can be provided in a part of the lithographic apparatus. Particles from the source (step (1)) remove at least a portion of this material (step (2)), thereby creating a deposit on the optical element. This is a secondary process shown as (b2b). The deposit on the optical element as a result of method (b2b) is a material derived from the material on the part of the device (a material comprising one or more elements selected from B, C, Si, Ge and / or Sn) ), But also Sn (according to the mechanism of (b1) and / or (b2)) from deposits on the source electrode.

  Furthermore, the same three methods / mechanisms also apply to non-Sn sources, which may include non-Sn materials on the electrodes. In the method (c1), the source is a non-Sn source, and there is non-Sn (ie, B, C, Si and / or Ge) on the electrode, and this material is deposited as an optical element, for example, a collector mirror. Is a way to bring. This is a primary process (indicated by step (1)). For example, non-Sn material from the electrode (step (1)) is deposited on a portion of the lithographic apparatus, and this deposit is then at least partially by particles from the source and / or non-Sn from the source electrode. Higher order processes are also included when they are removed (step (2)), thereby resulting in a non-Sn deposit comprising B, C, Si and / or Ge on the optical element. This latter process is shown as method (c2) in this table. This is a secondary process because it may include higher orders, but the material may be deposited and removed several times before finally depositing on the optical element.

  In one variant, the material according to the invention can be provided in a part of the lithographic apparatus. Particles from the source (step (1)) remove at least a portion of this material (step (2)), thereby creating a deposit on the optical element. This is a secondary process shown as (c2b). The deposit on the optical element as a result of method (c2b) is a material derived from the material on the part of the device (a material comprising one or more elements selected from B, C, Si, Ge and / or Sn) ), But also non-Sn materials from the source (according to method (c2)).

  Another method or arrangement is (d) where the source is a non-Sn source, for example a Li or Xe source and there is no material according to the invention on the electrode, but on a part of this device. Has this material. Particles from the source remove at least a portion of the material, thereby providing the optical element with a secondary process. In one embodiment, this method is used in combination with a laser excited plasma source.

  Methods (a2), (b2), and (c2) include redeposition methods, and methods (a2b), (b2b), and (c2b) may include redeposition. Further, method (d) may include redeposition (when some of the material on one part of the device is first deposited on the other part of the device). Preferred methods / structures include (a2), (a2b), (b1), (b2), (b2b), (c1), (c2), (c2b) and (d). Further desirable methods include (a2), (a2b), (b2), (b2b), (c2), (c2b) and (d). Even more desirable methods include (a2b), (b2b), (c2b), and (d), which provide material to a portion of the lithographic apparatus prior to use of the lithographic apparatus and includes secondary methods Is the method. The portion of the lithographic apparatus that includes this material preferably includes a gas barrier.

  One or more of the mechanisms (a1), (a2), (a2b), (b1), (b2), (b2b) provide Sn in the Sn source, for example, one or more Sn One or more of the mechanisms (a1), (a2), (a2b), (c1), (c2), (c2b) are applied to the method of the embodiment provided on the Sn electrode of the non-Sn material. It should be understood that this applies to the method of providing the source, for example the method of providing B, C, Si and / or Ge on one or more Sn electrodes.

  In one embodiment, the material is wetted and provided by coating and / or impregnation. For example, a part of the device, such as a gas barrier, is coated with a solution or suspension containing Sn, for example a solution containing a Sn salt such as stannic nitrate or stannic chloride, thereby A film or coating containing Sn may be provided on the portion. In still further embodiments, Sn is applied to a portion of the device (eg, heat shield, gas barrier, support, device wall, radiation source chamber wall, electrode, and / or device edge). Alternatively, one or more parts of this part may be provided by immersing in molten Sn. According to yet another embodiment of the invention, B, C, Si, Ge and / or Sn are provided by chemical vapor deposition on the part of the apparatus. This can be done before or after assembly of the device, and even during use, as described in US patent application Ser. No. 10 / 956,344, incorporated herein by reference.

  Furthermore, the part of the device may have a gas barrier comprising a surface that is at least partially porous, for example a surface layer comprising a porous W layer or a porous Mo layer. Such a porous structure may be desirable for methods such as wetting, coating and / or impregnation. In another embodiment, the material is provided by wetting with a metal, for example Sn. However, any other material that can be removed 1) at least partially by hydrogen or halogen after deposition on the optical element, and desirably 2) wettable may be used. Thus, in one embodiment, the material used includes a wettable material. In another embodiment, the portion of the lithographic apparatus that provides the material is used at a temperature that allows wetting. In another embodiment, the element or compound that can wet the surface of the part of the lithographic apparatus or the surface of the optical element is heated so that it wets over the entire surface. In another embodiment, the surface of the part of the lithographic apparatus or the surface of the optical element is controlled, for example, by a cooling element and / or a heating element.

  In another embodiment, a layer comprising an adhesion and / or wettability improving material is provided before applying this material to one or more parts (eg, gas barrier) or electrodes of the lithographic apparatus. For example, in order to improve the formation of the Sn layer on the gas barrier, the gas barrier may be at least partially provided with a Cu layer on its surface.

  According to another embodiment of the invention, the optical element includes a mirror, a grating, a reticle and / or a sensor, such as a collector mirror. In one embodiment, for example, when using Sn, the temperature of the optical element, eg, the collector mirror, can be adjusted to allow wetting of the material (see also above).

  According to another embodiment, a method for protecting an optical element for a lithographic apparatus comprising a radiation source, a part comprising a gas barrier, a support, an apparatus wall, a wall of a radiation source chamber, and / or an edge of the apparatus If the radiation source is in use, emit a plasma containing Sn; the method a) emitting a plasma containing Sn, thereby providing an Sn deposit on one or more parts of the lithographic apparatus B) providing the optical element to the apparatus; c) providing a plasma containing Sn, thereby providing a Sn deposit on the optical element.

  Here, (a) when there are no optical elements, such as mirrors, gratings, reticles and sensors, this source initially provides Sn in one or more parts of the lithographic apparatus. This provides Sn deposits (materials as described above) on one or more parts of the lithographic apparatus. Then, (b) providing the optical element to the lithographic apparatus. (C) The deposit or material is then at least partially removed from the parts of the lithographic apparatus during use and deposited on the optical element. Thus, at least part of the Sn deposit on one or more parts of the lithographic apparatus obtained during step a) is deposited on the one or more parts of the lithographic apparatus with particles from the radiation source during step c). It is removed by collision with an object or by one of the other mechanisms described above, such as irradiation, heating or the like. This method may be used in methods (a2), (a2b), (b2) and (b2b). In such an embodiment, the Sn source first provides material to the part of the lithographic apparatus in the absence of optical elements (only the primary process is performed) and then (after a sufficient layer of Sn has been created). ) Providing an optical element, which is substantially in a secondary process and receiving deposits. However, since direct deposition cannot be excluded, it may also undergo a primary process.

According to yet another embodiment, one or more of the above-described components of the lithographic apparatus has a radiation beam incident on one or more surfaces of these components and the deposited layer (ie, material) is at least Provided. The material comprising the material of this layer comprises a layer comprising BN, SiC, Si ₃ N ₄ , GeC, Ge ₃ N ₄ and a layer comprising an oxide and / or nitride of Si, Ge and / or Sn, and One or more selected from B, C, Si, Ge and / or Sn, such as a layer comprising an alloy comprising a compound comprising one or more elements selected from B, C, Si, Ge and / or Sn A compound containing an element or a number of compounds may be included. In one example, the layer includes at least about 20 wt%, such as 20-100 wt%, desirably at least about 35 wt% of the layer, such as 35-100 wt%, of one or more elements. The single element layer or nitride layer may contain oxygen impurities. In yet a further embodiment, the portion of the lithographic apparatus comprising a material comprising one or more elements selected from B, C, Si, Ge and / or Sn is approximately 20 to 100%, preferably about 40-100% of its surface, contains this material. In another example, the thickness of this layer is between about 5-200 μm, for example, between about 10-100 μm. In another embodiment, comprising a material according to the invention and receiving radiation directly from the source (ie within the line of sight with the plasma source), preferably 20-100% of the surface, preferably about 40-100 of the surface. This part of the device, which comprises%, has the above-mentioned layer thickness of between about 5 and 200 μm over 20 to 100%, preferably about 40 to 100% of its surface receiving radiation directly from the source .

In one embodiment, if material is provided to one or more electrodes of the source, this material does not include plasma material. In another embodiment, when this material is applied to an electrode, the material does not contain Sn (ie, non-Sn is applied to the electrode, in which case the electrode and the device using this electrode are non-Sn plasmas). Designed to provide, for example, Xe or Li plasma).
In yet a further embodiment of the invention, the optical element includes a protective layer, eg, a protective layer comprising Sn, prior to use in the device. This may be a layer of about 1 nm to 100 nm. In yet a further embodiment, this layer is about 2-20 nm. In another embodiment, the layer has a layer thickness of about 5-20 nm, such as 5-10 nm.
In another embodiment of the invention, an illumination system in which the lithographic apparatus is configured to condition a radiation beam; a patterning device configured to pattern a cross section of the beam of radiation to produce a patterned radiation beam A substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; an optical element; a radiation source; From a gas barrier, the support, the device wall, the wall of the radiation source chamber, and / or the edge of the device having a deposit comprising one or more elements selected from C, Si, Ge and / or Sn Including a portion of the selected lithographic apparatus; the deposit has a layer thickness of 5 to 200 μm. In addition, the electrode may include such a deposited layer.

  In one example, the optical element is a mirror, grating, reticle and / or sensor, eg, a collector mirror. According to another embodiment, the apparatus is a lithographic apparatus for EUV lithography.

  The protective layer on this optical element can be removed by providing atomic hydrogen or halogen gas or combinations thereof, as described in US patent application Ser. No. 10 / 956,344, incorporated herein by reference. . Thus, in yet further embodiments, the material used can be at least partially removed from the optical element by hydrogen or halogen after deposition on the optical element.

  In the context of the present invention, an “optical element” is an optical filter, an optical grating, a mirror such as a multilayer mirror, a grazing incidence mirror, a normal incidence mirror, a collector mirror (eg, US Pat. Alignment sensors such as lenses, reticles, diodes, sensors, eg intensity measuring sensors, energy sensors, CCD sensors, optical alignment sensors, etc., as described in 2004 / 0094724A1 and as shown in FIGS. Gas barriers (eg, as described in US Pat. Nos. 6,614,505, 6,359,969, and 6,576,912, incorporated herein by reference), etc. One or more elements selected from: The gas barrier is also called a contaminant filter, a debris filter, a debris suppression means, a foil trap, or the like. Optical elements, such as filters, gratings, mirrors or lenses, may be flat or curved and may exist as layers, foils, devices, and the like. In one embodiment of the present invention, the optical filter, optical grating, mirror, such as multilayer mirror, grazing incidence mirror, normal incidence mirror, collector mirror, lens, etc. may have a predetermined wavelength λ (5-20 nm, ie EUV radiation). For example, about 13.5 nm; 248 nm; 193 nm; 157 nm; or 126 nm, etc.). They may also be transparent to radiation of wavelength λ, for example in the case of lenses, or reflective, for example in the case of mirrors, or diffracted, for example in the case of gratings. May be sex. Certain optical elements may have one or more of these optical effects, see, for example, European Patent Application No. 03077850, incorporated herein by reference. As used herein, the terms “radiation” and “beam” refer to ultraviolet (UV) radiation (eg, having a wavelength λ of 365, 248, 193, 157 or 126 nm) and extreme ultraviolet (EUV or soft x-ray) radiation ( Including all types of electromagnetic radiation including particle beams, such as ion beams or electron beams. In general, radiation having a wavelength between about 780 and 3000 nm (or greater) is considered IR radiation. UV refers to radiation having a wavelength of approximately 100-400 nm. In lithography, it is also applied to the wavelengths that can usually be produced by mercury discharge lamps: G-line 436 nm; H-line 405 nm; I-line 365 nm. VUV is vacuum UV (i.e., UV absorbed by air) and refers to wavelengths of approximately 100-200 nm. DUV is used for wavelengths produced by excimer lasers, such as 126 nm to 248 nm in deep UV, usually in lithography. For example, it should be understood that radiation having a wavelength in the range of 5-20 nm refers to radiation having a certain wavelength bandwidth, at least a portion of which is in the range of 5-20 nm.

  As used herein, the term “layer” may describe a layer that has one or more interfaces with other layers and / or other media, such as a vacuum (in use), as should be understood. I don't know. However, it should be understood that “layer” may also mean part of a structure. The term “layer” may also refer to a number of layers. These layers can be, for example, next to each other or overlap each other. They may also include a single material or combination of materials. It should also be noted that the term “layer” as used herein may describe a continuous or discontinuous layer. In the present invention, the term “material” may also be interpreted as a combination of materials. Material refers to additional material on an existing surface, such as a deposit containing material provided to the device wall. During the operating state, this material is solid (eg, Si coating) or liquid (eg, Sn wettable material). The term “deposit” herein refers to a material that is chemically or physically attached to a surface (eg, the surface of an optical element), as is known to those skilled in the art. Such deposits may be layers, but may also include multilayer structures. This deposit may also include redeposited products or evaporated products. The material can be provided as a deposit. The term “element” in the phrase “one or more elements selected from B, C, Si, Ge and / or Sn” as used herein, as known to those skilled in the art, includes these elements, Or a material, deposit or redeposit, or a combination thereof, containing molecules containing such elements, or containing compounds containing these elements (Si oxide, Si carbide, Sn salt, Sn oxide, etc.) Point to. The phrase “a deposit comprising one or more elements selected from B, C, Si, Ge and / or Sn” refers to a single layer or multiple layers comprising atoms B, C, Si, Ge and Sn and combinations thereof, for example May refer to a single layer or multiple layers containing metal Sn.

  The term “depositable material” is a material that includes one or more elements selected from B, C, Si, Ge and / or Sn and is (i) emitted from an electrode and / or (ii) from a plasma. And / or (iii) removed from the material on the part of the lithographic apparatus, for example by particles from the electrodes or by another mechanism such as thermal irradiation or irradiation (ablation) by a radiation source, And what can be deposited on an optical element. In general, it is a material that can form a deposit according to the present invention, that is emitted as particles from the surface, thereby depositable material (particles, elemental particles), ie a material that can be deposited on an optical element make. The phrase “material comprising one or more elements selected from B, C, Si, Ge and / or Sn” refers to compounds (eg, Si oxide, Sn oxide), carbides, metals and B, C, Si , Ge and / or Sn elements, but may also refer to one or more alloys of these elements, such as Cu-Sn alloys. Here, “Sn material” is used as a shorthand notation for electrodes used to prepare Sn plasma for use in a lithographic apparatus. Here, “Sn material” is used as a definition of a material containing Sn. Such a material includes at least Sn, although it may also include other elements including, for example, Si, B, Ge and / or C. The term “non-Sn electrode” refers to an electrode used to create a non-Sn plasma, eg, a Li or Xe plasma. Nevertheless, such an electrode can be coated, wetted or impregnated with a Sn-containing material so that the plasma also contains Sn particles, eg, for thermally induced release of Sn material from the electrode. Good. The term “non-Sn material” refers to a material that is substantially free of Sn (<1 wt%).

  The term “primary” process or mechanism refers to a process in which material emitted from an electrode or from a plasma is deposited on an optical element without being deposited elsewhere. All materials deposited on the parts of the lithographic apparatus, released by particles from the source, and then deposited on the optical element are deposited in a secondary or higher order process (depending on the number of redeposition steps).

Some examples will now be described in more detail.
FIG. 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. The apparatus 1 includes an illumination system (illuminator) IL configured to condition a radiation beam PB (eg, UV radiation or EUV radiation). A first positioning device PM configured to support a patterning device (eg mask) MA by a support (eg mask table) MT and to accurately position the patterning device according to certain parameters. It is connected. A second positioning device constructed such that a substrate table (for example, a wafer table) WT holds a substrate (for example, a wafer coated with a resist) W and is configured to accurately position the substrate in accordance with certain parameters. Bonded to PW. A projection system (eg, a refractive projection lens system) PL is configured to project the pattern imparted to this radiation beam PB by the patterning device MA onto a target portion C (eg, including one or more dies) of the substrate W. It is.

  The illumination system may be a refractive, reflective, magnetic, electromagnetic, electrostatic or other type of optical component, or any combination thereof, for directing, shaping or controlling radiation Various types of optical components may also be included.

  This support supports the patterning device and carries, for example, its weight. It holds the patterning device in a manner that depends on its orientation, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device is held in a vacuum environment. The support can hold the patterning device using mechanical, vacuum, electrostatic or other clamping techniques. This support may be a frame or a table, for example, which may be fixed or movable as required. This support may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”

  As used herein, the term “patterning device” should be interpreted broadly to refer to a means that can be used to provide a cross-section of a radiation beam to a pattern that is created on a target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not correspond exactly to the desired pattern of the target portion of the substrate, for example, if the pattern includes a phase shift configuration or so-called auxiliary configuration. is there. In general, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in this target portion, such as an integrated circuit.

  The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. An example of a programmable mirror array uses a matrix arrangement of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirror imparts a pattern to the radiation beam reflected by this mirror matrix.

  As used herein, the term “projection system” refers to refractive, reflective, catadioptric, magnetic, as appropriate for the exposure radiation used or for other factors such as the use of immersion liquid or the use of vacuum. It should be construed broadly to encompass any type of projection system, including formula, electromagnetic and electrostatic optical systems, or any combination thereof. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

As depicted here, the apparatus is of a reflective type (eg, using a reflective mask). Alternatively, the apparatus may be transmissive (eg, using a transmissive mask).
The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such “multi-stage” machines, additional tables may be used in parallel, or the preparatory process may be performed on one or more tables, while one or more other tables may be used for exposure.

  The lithographic apparatus may be of a type wherein at least a portion of the substrate is covered with a relatively high refractive liquid, such as water, so as to fill a space between the projection system and the substrate. An immersion liquid may also be added to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. The term “immersion” as used herein does not mean that a structure, such as a substrate, must be submerged in a liquid, but rather that there is a liquid between the projection system and the substrate during exposure. It just means.

  Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. The source and the lithographic apparatus 1 may be separate entities, for example when the source is an excimer laser. In such a case, the source is not considered to form part of the lithographic apparatus, and radiation is emitted from the source SO using, for example, a beam delivery system BD including a suitable directing mirror and / or beam expander. To the illuminator IL. In other cases, for example when the source is a mercury lamp, the source may be part of the apparatus. This source SO and illuminator IL may be referred to as a radiation system, together with a beam delivery system BD if necessary.

  The illuminator IL may include an adjusting device configured to adjust the angular intensity distribution of the radiation beam. In general, at least the outer and / or inner radial extent (commonly referred to as σ outer and σ inner, respectively) of the intensity distribution at the pupil plane of the illuminator can be adjusted. Moreover, the illuminator IL may include various other components such as integrators and capacitors. The illuminator may be used to adjust the radiation beam to have a desired uniformity and intensity distribution in its cross section.

  The radiation beam PB is incident on the patterning device (eg, mask MA) held on the support (eg, mask table MT), and is patterned by the patterning device. After traversing the mask MA, the radiation beam PB passes through the projection system PS, which focuses this beam onto the target portion C of the substrate W. Using the second positioning device PW and the position sensor IF2 (e.g. interference measuring device, linear encoder or capacitive sensor), the substrate table WT is accurately adjusted, e.g. to place different target portions C in the path of the beam PB. Can be moved to. Similarly, using a first positioner PM and another position sensor IF1 (eg, an interferometer, linear encoder or capacitive sensor), eg, after mechanical retrieval from a mask library or during a scan The mask MA can be accurately positioned with respect to the path of the radiation beam PB. In general, the movement of the mask table MT may be realized using a long stroke module (coarse positioning) and a short stroke module (fine positioning) that form part of the first positioning device PM. Similarly, the movement of the substrate table WT may be realized using a long stroke module and a short stroke module which form part of the second positioning device PW. In the case of a stepper, unlike the scanner, the mask table MT may only be coupled to a short stroke actuator, or may be fixed. Mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The illustrated substrate alignment marks occupy dedicated target portions, but they may be in the spaces between the target portions (they are known as scribe lane alignment marks). Similarly, if more than one die is provided on the mask MA, the mask alignment mark may be between the dies.

The illustrated apparatus can be used in at least one of the following modes:
1. In step mode, the mask table MT and the substrate table WT are held essentially fixed while the entire pattern imparted to the radiation beam is projected onto the target portion C at once (ie, with a single static exposure). The substrate table WT is then moved in the X and / or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure area limits the size of the target portion C imaged in a single static exposure.
2. In the scanning mode, the mask table MT and the substrate table WT are scanned synchronously while a pattern given by the radiation beam is projected onto the target portion C (ie, single dynamic exposure). The speed and direction of the substrate table WT relative to the mask table MT depends on the (reduction) magnification and image reversal characteristics of the projection system PL. In the scanning mode, the maximum size of the exposure area limits the width of the target portion (in the non-scanning direction) in a single dynamic exposure, while the length of the scanning motion determines the height of the target portion (in the scanning direction).
3. In another mode, the mask table MT holding the programmable patterning device is essentially fixed and the substrate table WT is moved or scanned while the pattern imparted to the radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically used and the programmable patterning device is updated as needed after each movement of the substrate table WT or during successive radiation pulses during the scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.
Combinations and / or variations on the above described modes of use or entirely different modes of use may also be used.

  The term “lens” may refer to any one or combination of various types of optical elements, including refractive, reflective, magnetic, electromagnetic and electrostatic optical elements, if circumstances permit. .

  FIG. 2 shows the projection apparatus 1 in more detail, including a radiation system 42, an illumination optics unit 44, and a projection system PL. The radiation system 42 includes a radiation source SO, which may be formed by a discharge plasma EUV. EUV radiation can be produced by a gas or vapor that creates a very hot plasma in it and emits radiation in the EUV range of the electromagnetic spectrum, such as Xe gas, Li vapor or Sn vapor. This very hot plasma is created by crushing the partially ionized plasma of the discharge onto the optical axis O. To generate this radiation efficiently, a partial pressure of 10 Pa of Xe, Li, Sn vapor or other suitable gas or vapor may be required. Radiation emitted by the radiation source SO is sent from the source chamber 47 into the collector chamber 48 via a gas barrier or contaminant trap 49 (which is disposed in or behind the source chamber 47 opening). This gas barrier 49 is a channel, as described, for example, in US Pat. Nos. 6,614,505, 6,359,969, and 6,576,912, incorporated herein by reference. Includes structure.

  The collector chamber 48 includes a radiation collector 50 that may be formed by a grazing incidence collector. The radiation that has passed through the collector 50 is reflected from the grating spectral filter 51 and focused on the imaginary line origin of the opening 52 of the collector chamber 48. From the collector chamber 48, the radiation beam 56 is reflected in the illumination optical element unit 44 through the normal incidence reflectors 53 and 54 onto the reticle or mask located on the reticle or mask table MT. A patterned beam 57 is produced and imaged on the wafer stage or substrate table WT via the reflective elements 58, 59 in the projection optical system PL. More elements than shown may generally be present in the illumination optics unit 44 and the projection system PL.

  The radiation collector 50 may be, for example, the radiation collector described in US Patent Application Publication No. 2004/0094724 A1, incorporated herein by reference.

  All of the optical elements shown in FIG. 2 (and optical elements not shown in the schematic of this example), depending on the source, may, for example, deposit Sn and / or damage by other fast atoms and molecules such as Li. Easy to receive. This is especially true for the radiation collector 50 and the grating spectral filter 51 or spectral purity filter. Therefore, the method of the present invention can be applied to these optical elements as well as to the normal incidence reflectors 53 and 54 and the reflective elements 58 and 59.

Example 1
With reference to FIGS. 2 and 3, a material comprising one or more elements selected from B, C, Si, Ge and / or Sn is provided and if the source is in use, Arrange to remove at least a portion of this material, thereby providing a depositable material. This material is then applied to at least part of the source electrode 147, part of the wall 47a of the source chamber 47, part of the surface of the gas barrier 49, such as the channel plate 49a of the gas barrier 49, Radiation is applied to the edges of these plates, particularly to the source SO, to the edge of the opening 52, to the edge of the collimator mirror 50, to the support of the gas barrier 49, collimator mirror 50, mirror 51, mirrors 53 and 54. It may be provided on at least a part of the wall of the system 42 or the lighting system 44. Further, the material is provided such that at least a portion of the depositable material is deposited on the optical element. With this source, a portion of this material is removed, thereby creating a depositable material, which is redeposited in part of the opening or elsewhere, and at least one of the depositable materials. Part will be deposited on the optical element. This material is therefore provided on the electrode 147 of the source SO and / or on the parts of the lithographic apparatus between the source SO and the optical element. Optical elements protected by the method of the present invention include, for example, mirrors 50, 51, 53 and 54.

  In this way, instead of avoiding deposition, deposition is deliberately provided on the removable optical element. For example, due to collisions between particles from the source and parts of the lithographic apparatus, this material may be facilitated by other deposits such as hydrogen, halogen, or combinations thereof without providing the electrode or part of the lithographic apparatus. Al, Fe, Mo, W, etc. that cannot be removed are deposited on the optical element 50. The material according to the present invention is relatively easy by providing hydrogen radicals or by halogens, or combinations thereof, as described in US patent application Ser. No. 10 / 956,344, incorporated herein by reference. Can be removed. A hydride or halide is produced, which can be removed by getter and / or exhaust. In addition, hydrogen may also be provided, which can reduce compounds in this deposit, for example, reducing silicon oxide to Si, which can then be removed later by hydrogen radicals and / or halogens.

  In one variant, a wettable material such as Sn is used. This provides a smooth layer on the part of the device where this material is provided, but it may also provide a smooth layer by wetting the optical element 50. To this end, the optical element 50 may be subjected to external heating, for example as described in EP-A-0307836.1 and US patent application Ser. No. 10 / 956,344, incorporated herein by reference, or It may be heated to a wetting temperature (eg, 230-500 ° C. for Sn) by radiation from this source or both. The melting point of Sn is about 232 ° C. This wetting temperature depends on the surface and other parameters, including pressure.

  In one variant, all parts of the lithographic apparatus that are in line of sight with the plasma source and between the line source and the optical elements are the surfaces of these parts in line with the plasma source and line of sight (from the line source). About 20-100% of the surface that receives direct radiation is provided with this material. The thickness of this layer is between about 5 and 200 μm.

Example 2 (eg, methods (d), (a2b), (b2b) and (c2b))
2 and 3, in this embodiment, the optical element 50, that is, the collector mirror, is made of a material containing one or more elements selected from B, C, Si, Ge and / or Sn as a gas barrier. 49 to one or more selected from the group 49 (on the surface 49b and / or the edge 40c of the parallel element 49a), to at least part of the wall 47a of the source chamber 47 or one of these supports (in this schematic view (Not shown, but provided to a person skilled in the art, such as a support for a collector), so that the source removes at least a portion of this material if it is in use. This material is placed in a protective layer, thereby providing a depositable material. In use, at least a portion of this depositable material is deposited on the optical element 50. This creates a deposit on the optical element 50 that can be removed relatively easily with atomic hydrogen, halide gas, or both (see below).

  In one variant, this material is applied in situ to a part of the lithographic apparatus and removed from the optical element in situ according to the method described in US patent application Ser. No. 10 / 956,344.

Example 3 (eg, methods (a2), (b2) and (c2))
2 and 3, in this embodiment, the optical element 50, that is, the collector mirror, is made of one material containing one or more elements selected from B, C, Si, Ge and / or Sn. By providing the electrode 147, the protective layer protects it. In use, at least a portion of this material is removed from the electrode. The removal of at least a portion of this material is a result of the high temperature of this source leading to the release of particles containing depositable material. At least a portion of the depositable material is deposited on other parts of the apparatus, such as walls 47a, gas barriers 49 (parallel plates 49a), and the like. Due to the impact of the particles from the source SO, either from the electrode 147 or from the material on the electrode 147, this deposit is at least partially removed from these parts and deposited on the optical element 50. Make things. Primary deposition may also occur after these mechanisms (described below).

Example 4 (eg, methods (b1) and (c1))
2 and 3, in this embodiment, the optical element 50, that is, the collector mirror, is made of one material containing one or more elements selected from B, C, Si, Ge and / or Sn. Provided on the above electrode 147, (i) If the source is in use, it is protected with a protective layer by removing at least a portion of this material, thereby creating a depositable material. The removal of at least a portion of this material is a result of the high temperature of this source leading to the release of particles containing depositable material. In use, at least a portion of this depositable material is deposited on the optical element 50. When using these methods, the normal methods (a2), (b2) and (c2) will also occur.

Example 5 (Method (a1))
With reference to FIGS. 2 and 3, in this embodiment, the optical element 50, i.e. the collector mirror, uses a Sn source, and (i) if the source is in use, depositable material is used. By making it, it protects with the protective layer containing Sn. The removal of at least a portion of this material is a result of the high temperature of this source leading to the release of particles containing depositable material. In use, at least a portion of this depositable material is deposited on the optical element 50.

Example 6 (Method (a1) and Methods (b1) and (c1))
In this example, a plasma containing Sn by the source SO (either by an Sn electrode (eg, Example 5; see method (a1)) or because Sn is present on a non-Sn source (eg, Example 4). , Method (b1))) is provided and in the absence of an optical element, such as optical element 50, a deposit containing Sn is made on one or more parts of the lithographic apparatus; or a non-Sn material on the electrode (Example 4, method (c1)) results in deposits on one or more parts of the lithographic apparatus.

  Thereafter, this optical element is provided (step b). Next, the method is continued by preparing a plasma containing Sn, whereby Sn deposits are deposited on the optical element not only by mechanism (a1) or (b1) but also by mechanism (a2) or (b2). Making it that part of the deposit on the parts of the lithographic apparatus is also removed by fast particles from the source and / or Sn from the source; or the source is non-Sn particles or other fast particles This is because the non-Sn deposit is produced not only by the mechanism (c1) but also by the mechanism (c2).

  Prior to providing this optical element (step b), one has to place an “evidence sample” at the position of the optical element (for example, substantially the same dimensions as this optical element as known to those skilled in the art, For example, it may be desirable to test the performance of this lithographic apparatus by providing a device comprising Si). When not using the source SO, deposits could be this evidence sample. By measuring the composition of the material deposited on this evidence sample, in situ or off-site, it may be determined when the deposit containing Sn on one or more parts of the lithographic apparatus is sufficient. For example, in the case of Sn deposits, when the deposit contains 50 wt% or more, for example, 80-100 wt% Sn, the deposit containing Sn on one or more parts of the lithographic apparatus causes the optical element to It may be enough to be able to provide this device. If this value is not reached, Sn may be applied to one or more parts of the lithographic apparatus by other mechanisms such as in-situ or off-site sputtering, dip coating, wetting, and the like. Sputtering by Sn sources or other methods provided is typical when the resulting thickness of the layer comprising the material of the present invention has a layer thickness between about 5-200 μm, for example between about 10-100 μm. Is enough.

Example 7
Materials containing one or more elements selected from B, C, Si, Ge and / or Sn, eg, compounds such as Si oxide, Sn oxide, carbide, metal and B, C, Si, Ge and Sn Or an alloy of one or more of these elements, for example, a material containing a Cu-Sn alloy, to one or more gas barriers 49, to at least part of the wall 47a of the source chamber 47, and to support the electrode 147 Wet the body or one or more thereof and provide it by one or more of the following methods: coating and / or impregnation.

  Wetting is performed by heating a wettable compound of B, C, Si, Ge and / or Sn to the surface of a gas barrier, wall, electrode, etc. simultaneously and / or after, for example, by sputtering, CVD or PVD. Do it by attaching. This method may be used for Sn. To improve wetting, for example, the wall or gas barrier may include a Cu layer (eg, 10-100 nm) on which this wettable compound is provided. This method of wetting is possible according to US patent application Ser. No. 10 / 956,344, which is also incorporated herein by reference, such as in situ sputtering, CVD or PVD. Can be applied to any part.

  The coating can be by sputtering, CVD, PVD, dip coating (eg, in liquid Sn), spraying, etc., eg, nitrides, oxynitrides, oxides, or salts (chlorides, nitrates, etc.) The compound may be provided on the surface of a gas barrier, wall, electrode or the like as a solution or as a slurry. This method of coating can be applied to parts of the lithographic apparatus before the lithographic apparatus is assembled.

  Impregnation may be accomplished by dip coating, spraying, etc., for example, compounds such as nitrides, oxynitrides, oxides, or salts (chlorides, nitrates, etc.), in solutions or as slurries, gas barriers, walls As is well known to those skilled in the art, when the surface is porous (for example, 10 to 50 vol% of the material is the pore volume), it can be performed by providing it on the surface of the electrode or the like. This method of impregnation can be applied to parts of the lithographic apparatus before the lithographic apparatus is assembled.

Example 8
In this example, before using the gas barrier 49 in a lithographic apparatus having a Sn source or a source comprising an electrode 147 with Sn attached to one or more electrodes 147, first a thin Cu layer, eg, Cover with 10-100 nm. The inner surface, that is, the surface of the plate 49a has Cu attached to at least 20 to 50% of the total area of the surface.

  In a variant of this embodiment, the gas barrier comprises Cu and later comprises Sn. By heating, Sn gets wet over the entire surface of the gas barrier. The provision of Sn in the gas barrier may be performed before use in the apparatus.

Example 9
For example, with reference to Example 7 or Example 8, one or more parts of this device, such as gas barriers, supports, device walls, radiation source chamber walls, electrodes and / or device edges Immerse in a bath of molten Sn. For example, the component may be a Mo or W electrode, such as a gas barrier having a Mo or W coating. A layer of about 5 to 200 μm is provided before the device parts are attached to the device.

  In one variant, all parts of the lithographic apparatus that are within the line of sight of the plasma source and between the source and the optical elements are the surfaces of these parts within the line of sight of the plasma source (directly from the source). About 20-100% of the surface receiving radiation is provided with this material. The thickness of this layer is between about 5 and 200 μm.

  This process of applying the Sn coating to the part of the device is preferably performed during or prior to assembly of the device.

Example 10
The radiation source of this apparatus is a radiation source that supplies Sn plasma.

Example 11
In this embodiment, the radiation source is an Xe radiation source, and this material is provided in the gas barrier 49.

Example 12
This example illustrates deposition on the collector mirror 50. As can be seen in FIG. 3 of US Patent Application Publication No. 2004/0094724 A1, which is incorporated by reference, this grazing incidence collector 10 includes a number of nested reflector elements. Such a grazing incidence collector is also shown, for example, in German patent application DE 10138284.7. As shown in FIGS. 5 and 2, the collectors 50 are aligned along the optical axis, indicated by reference numeral 247 in FIG. This collector 50 may include several reflectors 142, 143, 146. An example of such a collector is shown in FIG. In FIG. 5, the inner reflector is indicated by reference numeral 142 and the outer reflector is indicated by reference numeral 146. There may be several other reflectors 143 between the reflectors 142 and 146, and their contours are shown in dashed lines in FIG. All reflectors 142 and 146 have reflective layers selected from the layers of reference numerals 154, 156, 158 and 159, such that their backing layer 152 is described in US Patent Application Publication No. 2004 / 0094724A1 or It is coated with a number of reflective layers. There may be other layers, such as layers 160 and 162, as described in US Patent Application Publication No. 2004 / 0094724A1, and one or more of them may also include a reflective layer.

  On one or more layers selected from the layers 154, 156, 158 and 159, the material according to the present invention may be provided as the layer 81, for example, 1 to 20 nm. Thereby, at least a part of the reflecting surface that receives radiation from the source SO and receives particles from the source SO is protected by the protective layer. The layer 81 may also be provided on the edge of these reflectors (shown on the left side (source side)). The layer 81 may be provided on the collector 50 prior to placing the collector 50 in the lithographic apparatus.

  FIG. 6 shows a collector 50 in which several heat dissipating fins 172 to 175 are attached to the outer reflector 146. These radiating fins 172 to 175 may be arbitrarily distributed in the outer reflector 146. The radiating fins 172-175 may further improve the thermal / infrared “blackbody” reflection characteristics of the collector 50. The edges of the reflectors 142, 143, 146 (etc.) may be provided with a layer 81 (not shown in FIG. 6), similar to the fins 172-175.

Example 13
Referring to FIG. 4, a gas barrier or contaminant barrier 49 includes two plates 49a from one of these contaminant barriers as described above to form one of the channels of this barrier, It has an edge 49c facing the source SO (not shown in this figure). The surface of the edge 49c and / or the surface 49b of the channel plate 49a can comprise a layer L of material according to the invention. Note that in this schematic view, the two plates 49a are not drawn substantially parallel.

  For example, the layer L can include about 20 wt%, for example, 20-100 wt% of one or more elements, such as Sn. In one variant, this layer L comprises metal Sn provided by CVD and / or wetting. This part of the lithographic apparatus preferably comprises this material on about 20-100% of its surface which receives radiation directly from the source, for example about 40-100% of its surface. In FIG. 4, the entire surface of the edge 49 c, the inner and outer surfaces 49 b of the plate 49 a include the layer L. This layer thickness is between about 5 and 200 μm, in one variant between about 10 and 100 μm. At least 20% of this layer L has this layer thickness, or the entire layer L comprising the material according to the invention has this layer thickness.

Example 14
With reference to FIGS. 7a and 7b, the layers according to the invention are schematically depicted. Figures 7a and 7b refer to optical elements, such as optical elements 50, 51, here denoted by reference numeral 80; or gas barrier 49, support (not explicitly shown in these figures), apparatus Walls (eg, walls 47a, but also other walls of other chambers), radiation source chamber walls (here, clearly walls 47a), electrodes 147, and edges of apertures 52 (notably visible in these figures) Not shown), heat shield (not explicitly shown in these figures), edge 49c of contaminant barrier plate 49a, etc., again indicated by reference numeral 80.

  Each such element or component has a surface, indicated schematically by reference numeral 80a. With reference to FIG. 7a, a portion of this surface, particularly the portion visible from the source, may comprise a layer 81 comprising the material of the present invention. When reference numeral 80 refers to an optical element, this layer will be about 1-100 nm, eg, about 5-20 nm, thereby providing a protective layer that is transparent to EUV.

  When reference numeral 80 refers to a portion of the device, the layer 81 has a thickness of between about 5-200 μm, for example between about 10-100 μm, whereby at least a portion of the material is Provides a layer that can be removed by one or more methods selected from the collision of the material with a particle from a radiation source, irradiation of the material, and transfer of thermal energy to the material, and thereby removable on the optical element Will result in a good deposit. For example, the layer 81 may include Sn, C, or Si.

  In one variation where reference numeral 80 refers to a portion of the device, layer 82 may be provided, for example, to improve wetting, which may be, for example, a Cu layer, or other layers known to those skilled in the art. .

  Although this specification may specifically refer to the use of a lithographic apparatus in the manufacture of ICs, the lithographic apparatus described herein includes integrated optical systems, inductive detection patterns for magnetic domain memories, flat panel displays, liquid crystals It should be understood that there are other applications such as the manufacture of displays (LCDs), thin film magnetic heads and the like. In the context of such alternative applications, it is understood that any of the terms “wafer” or “die” used herein may be considered synonymous with the more general terms “substrate” or “target portion”, respectively. It will be. The substrate referred to herein may be processed before or after exposure, for example, with a track (typically a device that applies a layer of resist to the substrate and develops the exposed resist), a measurement device and / or an inspection device. Good. Where applicable, this disclosure may be applied to such and other substrate processing tools. Furthermore, the substrate may be processed more than once, for example to create a multi-layer IC, so the term substrate as used herein may also refer to a substrate that already contains multiple processed layers.

  Although the above may have specifically referred to the use of embodiments of the present invention in the context of photolithography, the present invention may be used in other applications, for example, printing lithography, and as circumstances permit. You will find that you are not limited to photolithography. In printing lithography, the fine structure of the patterning device determines the pattern created on the substrate. The resist may be cured by pressing the patterning device microstructure against a layer of resist supplied to the substrate, where electromagnetic radiation, heat, pressure or a combination thereof is applied. After the resist is cured, the patterning device is moved out of the resist leaving a pattern in it.

  While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may be a computer program that includes one or more sequences of machine-readable instructions describing the methods disclosed above, or a data storage medium (eg, semiconductor memory, magnetic or optical disk) that stores such a computer program. May be included.

  The above description is intended to be illustrative and not limiting. Thus, it will be apparent that modifications may be made to the invention as described without departing from the scope of the claims set out below.

  The invention is not limited to lithographic apparatus applications or use in lithographic apparatus as described in the embodiments. Further, the drawings include elements and features necessary to understand the present invention. Otherwise, the drawing of the lithographic apparatus is schematic and not on scale. The invention is not limited to the elements shown in these schematics (eg, the number of mirrors drawn in these schematics). Further, the present invention is not limited to the lithographic apparatus described in the first embodiment and FIGS. It should be understood that the embodiments described above may be combined.

1 depicts a lithographic apparatus according to an embodiment of the invention. FIG. 2 is a side view showing an EUV illumination system and projection optics of the lithographic projection apparatus according to FIG. FIG. 3 is a detailed view of the lithographic apparatus shown in FIG. It is detail drawing of a gas barrier. It is an axial sectional view showing a collector mirror according to an embodiment of the present invention. The collector provided with a radiation fin is shown. 1 shows a layer comprising a deposit on an optical element or part thereof of a lithographic apparatus according to an embodiment of the invention; 1 shows a layer comprising a deposit on an optical element or part thereof of a lithographic apparatus according to an embodiment of the invention;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lithographic apparatus 47 Source chamber 47a Source chamber wall 49 Gas barrier 50 Collector mirror 51 Grating spectral filter 52 Aperture 53 Reflector 54 Reflector 147 Electrode C Target part IL Illumination system MA Patterning device MT Support PB Projection beam PL Projection System SO radiation source W substrate WT substrate table

Claims (15)

An optical element protection method for protecting an optical element from a contamination source in a lithographic apparatus, wherein the contamination source, in use, causes particles of the first material to be emitted by radiation emitted from the radiation source toward the optical element. A method for protecting an optical element comprising a first material emitted towards
When a second material containing one or more elements selected from B, C, Si, Ge and / or Sn is used, particles of the second material are released more than particles of the first material. A step of providing
Providing at least a portion of the emitted particles of the second material on the optical element;
At least a portion of the second material may be produced by colliding the particles from the radiation source with the second material, irradiating the second material, and / or transferring thermal energy to the second material. and a step of element-or et de method.   The method of claim 1, wherein the radiation source is a plasma source including a Xe radiation source, a Li radiation source, or a Sn radiation source.   The method of claim 1, wherein the second material is provided on at least a portion of a gas barrier of the lithographic apparatus.   2. The method according to claim 1, wherein the second material is provided on at least part of the support of the lithographic apparatus, the apparatus wall, the wall of the radiation source chamber and / or the edge of the opening.   2. The method of claim 1, wherein the second material is provided on at least a portion of an electrode of the radiation source.   2. A method according to claim 1, wherein the second material is wetted and applied by coating and / or impregnation. An optical element protection method for protecting an optical element from a contamination source in a lithographic apparatus, wherein, when the contamination source is in use, particles of the first material are caused by radiation emitted from the radiation source toward the optical element. A method for protecting an optical element comprising a first material emitted towards
When a second material containing one or more elements selected from B, C, Si, Ge and / or Sn is used, particles of the second material are released more than particles of the first material. A step of providing
Providing at least a portion of the emitted particles of the second material on the optical element;
Removing at least a portion of the second material from the optical element;
And wherein the second material is deposited on the optical element and then can be at least partially removed from the optical element by atomic hydrogen, or halogen, or a combination thereof. A method of protecting an optical element for a lithographic apparatus, wherein the lithographic apparatus is selected from the group comprising a radiation source and a gas barrier, a support, an apparatus wall, a chamber wall of the radiation source, and an edge of the opening Including the above parts, the method comprising:
a) activating the radiation source to generate a plasma containing Sn to provide Sn deposits on the one or more components;
b) actuating the radiation source to generate a Sn-containing plasma so as to provide a Sn deposit on the optical element, wherein one or more parts of the lithographic apparatus obtained during a) A method of removing at least a portion of the upper Sn deposit by collision of particles from the radiation source and Sn deposit on one or more parts of the lithographic apparatus during b). A method of manufacturing a device by using a lithographic apparatus having an optical element and a contamination source, wherein the contamination source, in use, causes particles of the first material to be emitted by radiation emitted from the radiation source toward the optical element. A second material comprising one or more elements selected from the group comprising B, C, Si, Ge and / or Sn, The material of 2 is a device manufacturing method in which the particles of the second material are more easily released than the particles of the first material in use,
Generating a radiation beam containing radiation from a radiation source;
Patterning the radiation beam;
Projecting a patterned beam of radiation onto a target portion of a substrate;
At least a portion of the second material may be produced by colliding the particles from the radiation source with the second material, irradiating the second material, and / or transferring thermal energy to the second material. and a step of element-or et de method. 10. The method of claim 9 , wherein the radiation source is a plasma source including a Xe radiation source, a Li radiation source, or a Sn radiation source. 10. A method according to claim 9 , wherein the second material is provided on a gas barrier of the lithographic apparatus. 10. A method according to claim 9 , wherein the second material is provided on the support of the lithographic apparatus, the apparatus wall, the wall of the radiation source chamber and / or the edge of the opening. The method according to claim 9 , wherein the second material is provided on an electrode of the radiation source. 10. A method according to claim 9 , wherein the second material is wetted and provided by coating and / or impregnation. A method of manufacturing a device by using a lithographic apparatus having an optical element and a contamination source, wherein the contamination source, in use, causes particles of the first material to be emitted by radiation emitted from the radiation source toward the optical element. A second material comprising one or more elements selected from the group comprising B, C, Si, Ge and / or Sn, The material of 2 is a device manufacturing method in which the particles of the second material are more easily released than the particles of the first material in use,
Generating a radiation beam containing radiation from a radiation source;
Patterning the radiation beam;
Projecting a patterned beam of radiation onto a target portion of a substrate;
Removing at least a portion of the second material from the optical element;
Hints, wherein the second material, the deposited on the optical element, atomic hydrogen or the halogen, which comprises a material that can be removed at least partially from the optical element.

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